Plasma processing apparatus and etching method

Abstract

According to one embodiment, a plasma processing apparatus includes a chamber, a substrate stage configured to support a substrate inside the chamber, and a plasma generation structure configured to generate plasma processing the substrate, in a space above the substrate inside the chamber. Further, the plasma processing apparatus includes an electromagnet including coils configured to apply a magnetic field to the space, and an electromagnet controller configured to cause pulsed electric currents, in each of which its direction and ON/OFF are pulsed, to flow through the coils.

What is claimed is: 
     
         1 . A plasma processing apparatus comprising:
 a chamber;   a substrate stage configured to support a substrate inside the chamber;   a plasma generation structure configured to generate plasma processing the substrate, in a space above the substrate inside the chamber;   an electromagnet including coils configured to apply a magnetic field to the space; and   an electromagnet controller configured to cause pulsed electric currents, in each of which its direction and ON/OFF are pulsed, to flow through the coils.   
     
     
         2 . The plasma processing apparatus according to  claim 1 , wherein the electromagnet controller is configured to cause the pulsed electric currents to flow through the coils in synchronism with each other. 
     
     
         3 . The plasma processing apparatus according to  claim 2 , wherein the electromagnet controller is configured to control the pulsed electric currents in accordance with sequence control information that prescribes the direction and ON/OFF of each of the pulsed electric currents in a predetermined period for each of the coils, such that the coils have starting time points of the predetermined period in synchronism with each other. 
     
     
         4 . The plasma processing apparatus according to  claim 3 , wherein the electromagnet controller is configured to repeatedly execute control over the pulsed electric currents prescribed in the predetermined period, by using the predetermined period as one cycle. 
     
     
         5 . The plasma processing apparatus according to  claim 3 , wherein
 the predetermined period includes a first period and a second period following the first period, and   the sequence control information prescribes the direction and ON/OFF of each of the pulsed electric currents such that the first period is set to have ions, which are being emitted from inside the plasma to the substrate, in a state tilted in a first direction not perpendicular to a processing face of the substrate, and the second period is set to have the ions in a state tilted in a second direction opposite to the first direction.   
     
     
         6 . The plasma processing apparatus according to  claim 1 , wherein the electromagnet is arranged above a top face of the chamber. 
     
     
         7 . The plasma processing apparatus according to  claim 6 , wherein the electromagnet includes the coils that have ring shapes and are arranged in a concentric state. 
     
     
         8 . The plasma processing apparatus according to  claim 7 , wherein each of the coils is divided into an n-number of arc-shaped coil segments, where “n” is an integer of 2 or more. 
     
     
         9 . The plasma processing apparatus according to  claim 1 , wherein the electromagnet is arranged around a lateral face of the chamber. 
     
     
         10 . The plasma processing apparatus according to  claim 9 , wherein the electromagnet includes the coils that have ring shapes and are arranged in a concentric state. 
     
     
         11 . The plasma processing apparatus according to  claim 10 , wherein each of the coils is divided into an n-number of arc-shaped coil segments, where “n” is an integer of 2 or more. 
     
     
         12 . The plasma processing apparatus according to  claim 3 , wherein the electromagnet controller includes
 a plasma control unit configured to cause an electric current to flow through one of the coils, and to change a direction of the electric current,   an electric current control unit configured to switch ON/OFF of the electric current flowing through a wiring line between the plasma control unit and the one of the coils, by a bias voltage at the wiring line, and   a sequence control unit configured to control the plasma control unit and the electric current control unit, in accordance with the sequence control information.   
     
     
         13 . An etching method comprising:
 supporting a substrate on a substrate stage inside a chamber;   generating plasma processing the substrate, in a space above the substrate inside the chamber; and   performing an etching process to the substrate, while applying a magnetic field to the space by causing pulsed electric currents, in each of which its direction and ON/OFF are pulsed, to flow through a coils of an electromagnet.   
     
     
         14 . The etching method according to  claim 13 , wherein, in the performing the etching process, the pulsed electric currents are caused to flow through the coils in synchronism with each other. 
     
     
         15 . The etching method according to  claim 14 , wherein, in the performing the etching process, the pulsed electric currents are controlled in accordance with sequence control information that prescribes the direction and ON/OFF of each of the pulsed electric currents in a predetermined period for each of the coils, such that the coils have starting time points of the predetermined period in synchronism with each other. 
     
     
         16 . The etching method according to  claim 15 , wherein, in the performing the etching process, control over the pulsed electric currents prescribed in the predetermined period is repeatedly executed by using the predetermined period as one cycle. 
     
     
         17 . The etching method according to  claim 15 , wherein
 the predetermined period includes a first period and a second period following the first period, and   the sequence control information prescribes the direction and ON/OFF of each of the pulsed electric currents such that the first period is set to have ions, which are being emitted from inside the plasma to the substrate, in a state tilted in a first direction not perpendicular to a processing face of the substrate, and the second period is set to have the ions in a state tilted in a second direction opposite to the first direction.   
     
     
         18 . The etching method according to  claim 13 , wherein the electromagnet is arranged above a top face of the chamber. 
     
     
         19 . The etching method according to  claim 18 , wherein the electromagnet includes the coils that have ring shapes and are arranged in a concentric state. 
     
     
         20 . The etching method according to  claim 19 , wherein each of the coils is divided into an n-number of arc-shaped coil segments, where “n” is an integer of 2 or more.